The present invention relates to a method for manufacturing a fiber reinforced elastic sheet, an apparatus for manufacturing the same and a mold to be used.
In general, there has been known a staple complex sheet to be used for a compression rubber layer of a transmission belt, a vibroisolating rubber, a cushioning material, a sealant, a shoe sole material, a floor material, a caterpillar cover material and the like if a base material is an elastomer, and to be used for a sliding member, a reinforcing parts and the like if the base material is a plastic.
Referring to the known manufacturing method, fiber orientation is random or is parallel with a sheet surface. The fiber orientation cannot fully be controlled so that uses are limited. In other words, most of the above-mentioned products exhibit the merits of staple complex, for example, compression resistance, abrasion resistance, slide and the like if the staples are mainly oriented in the perpendicular direction of a sheet surface (in a sheet thickness direction) or the like. However, it is difficult to orient the staples in the perpendicular direction to the sheet surface or the like.
Conventionally, there have been known methods for orienting the staples of the staple reinforced material.
(1) Calendaring method: The staples are mainly oriented uniaxially in a sheet length direction.
(2) extrusion molding method: The staples are mainly oriented uniaxially in the extrusion direction. In addition, Japanese Patent Publication No. 53-14239 has disclosed a method for orienting the staples out of the extrusion direction so as to obtain a ring extruded substance, while Japanese Patent Publication No. 58-29231 has disclosed a method for manufacturing a hose in which the radial component of the staple orientation exceeds the axial component thereof. However, the above-mentioned methods do not fully meet the requirement for high orientation. Furthermore, it is impossible to obtain a uniform sheet having a large width. More specifically, a fixed portion of an inside mold causes the turbulence of a material so that the orientation is partially disturbed.
(3) Injection molding method: The staples are mainly oriented in the flow direction of the material. It is difficult to wholly orient the staples in a constant direction.
(4) Laminating method: Japanese Unexamined Patent Publication No. 60-219034 has disclosed a method for laminating a lot of sheets, in which the staples are mainly oriented in the sheet length direction by calendering or extrusion, in the same direction and then cutting the sheets at a constant width so as to obtain a sheet in which the staples are mainly oriented in the direction of a minimum dimension (thickness). However, processing is troublesome. Accordingly, it is substantially difficult to obtain the sheet having a large area.